1. Field of the Invention
The present invention relates to a handsfree communication control method, a portable radio communication apparatus and a handsfree system, which are capable of appropriately maintaining or interrupting a connection of a portable radio communication apparatus with a mobile communication network when a handsfree short-range communication link is disconnected during a handsfree phone conversation using the portable radio communication apparatus in, for example, an automobile.
2. Description of the Related Art
A communication procedure for making a handsfree phone conversation through a portable radio communication apparatus in an automobile is defined as a handsfree profile (hereinafter referred to as HFP). According to the HFP, the portable radio communication apparatus is connected to a car-installed handsfree apparatus through a short-range communication means (e.g., short-range radio communication such as Bluetooth™) to configure a handsfree system, thereby allowing a handsfree phone conversation in an automobile through a mobile communication network. When a link using the short-range communication means (hereinafter referred to as a short-range communication link) is suddenly disconnected during a handsfree phone conversation (hereinafeter referred to as link loss), the portable radio communication apparatus is automatically disconnected from the mobile communication network unless the short-range communication link is connected again within a predetermined period of time.
However, the HFP does not define whether the short-range communication link is disconnected by a normal procedure or a with link loss with no procedures when, for example, the engine of an automobile is stopped. The short-range communication link can thus be disconnected by a normal procedure according to the design specifications of the handsfree apparatus. Furthermore, the HFP does not define whether a connection of the portable radio communication apparatus with the mobile communication network is maintained or interrupted when the short-range communication link is disconnected by a normal procedure. This connection is therefore maintained or interrupted according to the design specifications of the portable radio communication apparatus.
In view of the above, a user thinks that the portable radio communication apparatus is automatically disconnected from the mobile communication network if the user stops the engine of his or her automobile. Actually, however, the connection can possibly be continued and so can be accounting therefor. On the other hand, even though a user wishes to continue a phone conversation using a portable radio communication apparatus after he or she stops the engine of his or her automobile, the apparatus can possibly be disconnected regardless of the user's intention.
For example, Jpn. Pat. Appln. KOKAI Publication No. 2002-300648 discloses a conventional handsfree apparatus that controls a connection between a portable radio communication apparatus and a mobile communication network by monitoring a status of a short-range communication link associated with the portable radio communication apparatus (see page 2 and FIG. 1). The conventional handsfree apparatus has a function of monitoring the status of the short-range communication link to prevent calling and charging from continuing by methods of displaying an alarm, invalidating an input operation, disconnecting the apparatus from the mobile communication network, etc. when the status of the link is not good.
However, the above conventional handsfree apparatus has the problem that the maintenance or interruption of a connection of the portable radio communication apparatus with the mobile communication network cannot properly be controlled with user's intention when the short-range communication link is disconnected.
Accordingly, it is an object of the present invention to provide a handsfree communication control method, a portable radio communication apparatus and a handsfree system, which are capable of appropriately maintaining or interrupting a connection of a portable radio communication apparatus with a mobile communication network when a short-range communication link is disconnected.